When employing seats of this type it is desirable that the belt forces incidental to the occurrence of an occupant restraining load be directed, as far as is possible, directly into the vehicle substructure. However, in the case of motor vehicle seats adapted for longitudinal adjustment. It is desirable that the shackles accommodating the belt locks be mounted so as to permit movement in unison with the seat.
In accordance with the German Offenlegungsschrift DE-OS No. 24 00 898, the shackle accommodating a belt lock is arranged so as to completely embrace the lower track. The lower track is provided with toothing to enable a catch of the shackle to engage therein if, as the result of an accident, the shackle has been deformed by the tensile forces acting on the belt. This arrangement will provide that the shackle is coupled with the lower track. The arrangement is such that, during normal seat adjusting movement, the catch is prevented from engagement with the toothing, so that the shackle will not interfere with the fore and aft adjusting movement.
The motor vehicle seats described in DE-OS No. 20 27 884 and DE-OS No. 28 26 634 are functioning in substantially the same fashion. The operation in all these prior art vehicle seats is such that the components provided for accommodating the belt lock will not interfere with the longitudinal seat adjustment movement, but that at the instant of an occupant restraint load on the belt, a solid connection will be established between the seat belt lock and the lower track member.
One disadvantage inherent in these prior art vehicle seats is that catch means must be provided on the lower track over the entire seat adjusting range for the shackle accommodating the belt lock, as well as for the seat position locking device, and that two locking mechanisms are needed, i.e., one which will be operatively effective during normal longitudinal seat adjusting movement, and another one which in the event of an occupant restraint load on the belt, is adapted to lock the shackle accommodating the belt lock to the lower track.
It is the object of the present invention to incorporate means in a motor vehicle seat of the type described above which, while employing only one single latching mechanism and using a minimum amount of material, enable the seat to be fixed into selective longitudinal positions, and the shackle accommodating the seat belt buckle to be locked into position.